New York State's 2015-16 budget includes $5 million for a plan to combat nitrogen pollution on Long Island, an issue that has gained attention in recent years as algal blooms closed shellfishing areas, killed sea grass and harmed fisheries.

Lawmakers said the plan would guide government policy and funding on issues such as wastewater infrastructure that affect water quality.

"This plan will enable us as legislators to have the ammunition to justify additional investments into everything from additional sewers and water-treatment facilities as well as drinking water source areas such as the pine barrens," Assemb. Steve Englebright (D-Setauket) said last week.

The Department of Environmental Conservation and the Long Island Regional Planning Council are to split the funding and collaborate on the plan, officials said. It may also include a study into the sources of nitrogen pollution by Stony Brook University researchers, Englebright said.

Scientists say a lack of sewers in much of Suffolk County has fueled the algal blooms that have grown more common over the past three decades. Nitrogen from human waste seeps from septic systems and cesspools into bays and ponds, causing the algae to grow.

Englebright, Sen. Kenneth LaValle (R-Port Jefferson) and Assemb. Fred Thiele (I-Sag Harbor) led the push for the funding, which was supported by other Long Island lawmakers.

Legislators said the effort may result in regulatory standards for the amount of nitrogen allowed to flow into the environment from various sources, a goal environmental activists have sought for several years.

"I see all of this as an extremely good first step," said Bob DeLuca, president of the environmental organization Group for the East End. "In a way, it's a recognition of what science has taught us over the last 30 years."

Thiele said a numeric standard for nitrogen could vary by area and "might be different in agricultural areas than it might be in the pine barrens, for example."

Funding for the plan was also supported by the Nature Conservancy, an environmental group; the Long Island Association, a business group; and the Long Island Builders Institute, which represents tradespeople and developers.

"It's not just a study, it's a plan," said Jessica Ottney, director of government relations for the Nature Conservancy. "Our goal is to make sure it's not just a plan that sits on a shelf but one that's actually implemented."

Mitchell Pally, chief executive of the Long Island Builders Institute, said the effort would provide clarity for builders and "help inform the best infrastructure alternatives to meet these standards and coordinate actions between state regulators, counties, towns and villages."

The budget also includes $3 million for a Stony Brook University institute, spearheaded last year by Southampton Town Supervisor Anna Throne-Holst, for developing more efficient septic systems, Thiele said.

A $100 million incentive program to help homeowners upgrade septic systems on eastern Long Island, requested in February by the leaders of five towns and 10 villages on the East End, was not included in the budget.

But Thiele said hundreds of millions of dollars in infrastructure funds could potentially be tapped for water-quality projects on Long Island.